KR101644046B1 - Liquid crystal device - Google Patents

Abstract

A liquid crystal display device is provided. A liquid crystal display device according to an embodiment of the present invention includes a first substrate, a second substrate facing the first substrate, an electric field generating electrode formed on at least one of the first substrate and the second substrate, And a liquid crystal layer interposed between the first substrate and the second substrate and having a liquid crystal and an orientation polymer. Here, the alignment polymer is formed by irradiating the liquid crystal and the alignment assistant with light, and the alignment assistant comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, wherein the alignment aid is electrically neutral or semi- It is neutral.

Liquid crystal, orientation aid, afterimage

Description

[0001] Liquid crystal device [0002]

The present invention relates to a liquid crystal display device.

BACKGROUND ART [0002] Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. The liquid crystal display device includes two display panels on which an electric field generating electrode is formed and a liquid crystal layer interposed therebetween. A voltage is applied to the electric field generating electrode to generate an electric field in the liquid crystal layer to determine the direction of the liquid crystal molecules in the liquid crystal layer And controls the transmittance of light passing through the liquid crystal layer.

In a liquid crystal display, liquid crystal is very important for controlling a light transmittance to obtain a desired image. Particularly, as the use of liquid crystal display devices becomes diversified, various characteristics such as low voltage driving, high voltage holding ratio (VHR), wide viewing angle characteristics, wide operating temperature range, and high speed response are required.

The liquid crystal layer includes a liquid crystal composition in which various kinds of liquid crystals are mixed to satisfy various properties.

On the other hand, initial orientation is important in liquid crystal.

The pretilt of the liquid crystal should be uniformly controlled in order to improve the initial alignment of the liquid crystal. If the linear alignment of the liquid crystal is not uniform, the initial alignment of the liquid crystal is disturbed and it is difficult to control the light passing through the liquid crystal layer. In this case, not only the contrast ratio is lowered but also the difference in line inclination is visually recognized as a residual image from the outside, so that the display characteristic may become poor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device capable of reducing the afterimage of a liquid crystal display device caused by a difference in line inclination of liquid crystal and improving display characteristics.

A liquid crystal display according to an embodiment of the present invention includes a first substrate, a second substrate facing the first substrate, an electric field generating electrode formed on at least one of the first substrate and the second substrate, And a liquid crystal layer interposed between the substrate and the second substrate and having a liquid crystal and an orientation polymer. Wherein the alignment polymer is formed by irradiating the liquid crystal and the alignment aid with light, and the alignment aid comprises a methogen having a halogen atom and a photopolymerizable group bonded to the mesogen, wherein the alignment aid is electrically neutral It is semi-neutral.

The halogen atom is connected to the aromatic ring between the light-curing groups and may be positioned to be structurally symmetric.

The mesogen may be one of naphthalene, biphenyl and bisphenol A to which the halogen atom is bonded.

The halogen atom may include one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine.

The light curing agent may include at least one selected from an acryl group and a methacryl group.

The alignment aid may be represented by any one of the following formulas (1) to (8)

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

Lt; RTI ID = 0.0 > (I) < / RTI >

The alignment aid may be contained in an amount of 0.1 wt% to 0.5 wt% with respect to the content of the liquid crystal.

The electric field generating electrode may have a plurality of fine slits.

The first substrate may be a thin film transistor substrate, the second substrate may be a common electrode substrate, and at least one of a color filter and a black matrix may be formed on the thin film transistor substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: forming a first display panel having pixel electrodes formed thereon; forming a second display panel having common electrodes formed thereon; Forming a liquid crystal layer including a liquid crystal and an alignment aid between the first display panel and the second display panel; applying a voltage between the pixel electrode and the common electrode; And irradiating the liquid crystal layer with light while applying a voltage between the common electrodes to photo-polymerize the alignment assistant. Herein, the alignment assistant comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, wherein the alignment aid is electrically neutral or quasi-neutral.

The halogen atom is connected to the aromatic ring between the light-curing groups and may be positioned to be structurally symmetric.

The mesogen may be one of naphthalene, biphenyl and bisphenol A to which the halogen atom is bonded.

The halogen atom may include one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine.

The light curing agent may include at least one selected from an acryl group and a methacryl group.

The alignment aid may be represented by any one of the following formulas (1) to (8)

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

≪ / RTI > and at least one selected from compounds represented by formula

The voltage applied to the pixel electrode and the common electrode may be a DC voltage, and the DC voltage may be 5V to 20V.

And irradiating the liquid crystal layer with light in a state in which the voltage is turned off to the pixel electrode and the common electrode.

Energy irradiating the pixel electrode and the light-off in a state in which a voltage to the common electrode may be 20J / _cm ² to 60J / _cm ^2.

And the energy for irradiating the light with the voltage applied to the pixel electrode and the common electrode may be 5 J / _cm ² to 10 J / _cm ² .

At least one of a color filter and a black matrix is formed on the first display panel, and light can be emitted to the liquid crystal layer through the second display panel.

A liquid crystal composition according to another embodiment of the present invention includes a liquid crystal and an orientation polymer. Here, the alignment polymer is formed by irradiating the liquid crystal and the alignment assistant with light, and the alignment assistant comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, wherein the alignment aid is electrically neutral or semi- It is neutral.

The halogen atom is connected to the aromatic ring between the light-curing groups and may be positioned to be structurally symmetric.

The mesogen may be one of naphthalene, biphenyl and bisphenol A to which the halogen atom is bonded.

The halogen atom may include one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine.

The alignment aid may be represented by any one of the following formulas (1) to (8)

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

Lt; RTI ID = 0.0 > (I) < / RTI >

The alignment aid may be contained in an amount of 0.1 wt% to 0.5 wt% with respect to the content of the liquid crystal.

As described above, according to the present invention, the liquid crystal display device can uniformly control the line inclination of the liquid crystal by including the alignment aid, and at this time, the remaining amount of the unpolymerized alignment aid remaining in the liquid crystal layer Can be reduced. This can reduce the afterimage that may occur due to the unpolymerized alignment aid and improve the display characteristics.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Also, when a layer is referred to as being "on" another layer or substrate, it may be formed directly on another layer or substrate, or a third layer may be interposed therebetween. Like numbers refer to like elements throughout the specification.

1 is an equivalent circuit diagram of a pixel of a liquid crystal display according to an embodiment of the present invention.

Referring to FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes a thin film transistor panel 100, a common electrode panel 200, and a liquid crystal layer 3 interposed therebetween .

The liquid crystal display device includes a signal line including a plurality of gate lines GL, a plurality of data lines DLa and DLb and a plurality of sustain electrode lines SL and a plurality of pixels PX connected thereto.

Each pixel PX includes a pair of subpixels PXa and PXb and the subpixels PXa and PXb are connected to the switching elements Qa and Qb and liquid crystal capacitors Clca and Clcb and a storage capacitor, (Csta, Cstb).

The switching elements Qa and Qb are three terminal elements such as a thin film transistor provided on the lower panel 100. The control terminal is connected to the gate line GL and the input terminal is connected to the data lines DLa and DLb. And the output terminal is connected to the liquid crystal capacitors Clca and Clcb and the storage capacitors Csta and Cstb.

The liquid crystal capacitors Clca and Clcb are formed by using the sub-pixel electrodes 191a and 191b and the common electrode 270 as two terminals and the liquid crystal layer 3 between the two terminals as a dielectric.

The storage capacitors Csta and Cstb serving as auxiliary capacitors of the liquid crystal capacitors Clca and Clcb are formed by stacking the sustain electrode lines SL and the sub pixel electrodes 191a and 191b provided in the lower panel 100, And a predetermined voltage such as the common voltage Vcom is applied to the sustain electrode lines SL.

The voltages charged in the two liquid crystal capacitors (Clca, Clcb) are set so as to slightly differ from each other. For example, the data voltage applied to the liquid crystal capacitor Clca is always set to be lower or higher than the data voltage applied to the liquid crystal capacitor Clcb. By appropriately adjusting the voltage of the two liquid crystal capacitors Clca and Clcb, the image viewed from the side can be brought close to the image viewed from the front, thereby improving the lateral visibility of the liquid crystal display device.

FIG. 2 is a layout diagram of a liquid crystal display device according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line III-III 'of FIG. 4 is a plan view showing a pixel electrode. 5 is a plan view showing a basic electrode in a liquid crystal display device according to an embodiment of the present invention.

2 and 3, a liquid crystal display according to an exemplary embodiment of the present invention includes a lower panel 100 and an upper panel 200 facing each other, and a liquid crystal layer (3).

First, the lower panel 100 will be described.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 and 135 are formed on the insulating substrate 110.

The gate line 121 transmits the gate signal and extends mainly in the horizontal direction. Each gate line 121 includes a plurality of first and second gate electrodes 124a and 124b protruding upward.

The sustain electrode line includes a stem 131 extending substantially in parallel with the gate line 121 and a plurality of sustain electrodes 135 extending therefrom.

The shape and arrangement of the sustain electrode lines 131 and 135 may be modified in various forms.

A gate insulating layer 140 is formed on the gate line 121 and the sustain electrode lines 131 and 135. A plurality of semiconductors 154a and 154b made of amorphous or crystalline silicon are formed on the gate insulating layer 140, Respectively.

A plurality of pairs of ohmic contacts 163b and 165b are formed on the semiconductors 154a and 154b and the resistive contact members 163b and 165b are formed by doping silicide or n-type impurities at a high concentration Such as n + hydrogenated amorphous silicon.

A plurality of pairs of data lines 171a and 171b and a plurality of pairs of first and second drain electrodes 175a and 175b are formed on the resistive contact members 163b and 165b and the gate insulating layer 140 Respectively.

The data lines 171a and 171b transmit data signals and extend mainly in the vertical direction and cross the gate lines 121 and the stem lines 131 of the sustain electrode lines. The data lines 171a and 171b include first and second source electrodes 173a and 173b extending toward the first and second gate electrodes 124a and 124b and bent in a U shape, The second source electrodes 173a and 173b face the first and second drain electrodes 175a and 175b around the first and second gate electrodes 124a and 124b.

The first and second drain electrodes 175a and 175b extend upward from one end partially surrounded by the first and second source electrodes 173a and 173b respectively and the opposite end may have a large area for connection with another layer have.

However, the shapes and arrangements of the data lines 171a and 171b including the first and second drain electrodes 175a and 175b may be modified into various forms.

The first and second gate electrodes 124a and 124b and the first and second source electrodes 173a and 173b and the first and second drain electrodes 175a and 175b are electrically connected to the first and second semiconductors 154a and 154b, And the channel of the first and second thin film transistors Qa and Qb is connected to the first and second source electrodes (Qa and Qb) 173a and 173b and the first and second semiconductors 154a and 154b between the first and second drain electrodes 175a and 175b.

Resistive contact members 163b and 165b are present only between the underlying semiconductor layers 154a and 154b and the data lines 171a and 171b and drain electrodes 175a and 175b thereon and reduce contact resistance therebetween. Semiconductors 154a and 154b are exposed between the source electrodes 173a and 173b and the drain electrodes 175a and 175b as well as between the data lines 171a and 171b and the drain electrodes 175a and 175b.

A lower protective film 180p made of silicon nitride or silicon oxide is formed on the data lines 171a and 171b, the drain electrodes 175a and 175b and the exposed semiconductor portions 154a and 154b.

A partition wall 361 is formed on the lower protective film 180p. The barrier ribs 361 are formed along the gate lines 121 and the data lines 171a and 171b, and are also formed over the thin film transistors. The region enclosed by the barrier ribs 361 is a filling region filled with the color filter 230 and the upper protective film 180q and has a substantially rectangular shape.

The barrier rib 361 includes a first barrier rib 361a formed on the thin film transistor and a second barrier rib 361b formed on the data lines 171a and 171b. Specifically, the first bank 361a has an opening G for exposing the first and second drain electrodes 175a and 175b. The second bank 361b is formed so as to partially overlap the data lines 171a and 171b in the region between the neighboring data lines 171a and 171b.

The ink-jet color filter 230 is filled in the region surrounded by the barrier ribs 361. The color filter 230 may be formed by an inkjet printing method. On the color filter 230, an upper protective film 180q is formed. The upper protective film 180q is formed to extend over the barrier ribs 361 and serves to planarize the layer formed at the lower end of the upper protective film 180q.

The upper protective film 180q may be formed of an organic material having photosensitivity. The upper protective film 180q is formed with a plurality of contact holes 185a and 185b for exposing the first and second drain electrodes 175a and 175b in addition to the opening G. [

A plurality of pixel electrodes 191 are formed on the upper protective film 180q. The pixel electrode 191 may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver, chromium, or an alloy thereof.

Each of the pixel electrodes 191 includes first and second sub-pixel electrodes 191a and 191b which are separated from each other with a gap 91 therebetween. The first and second sub-pixel electrodes 191a and 191b Each of which includes at least one of the basic electrode 199 shown in FIG. 5 or a modification thereof.

4 and 5, the basic electrode 199 will be described in detail.

As shown in FIG. 5, the overall shape of the base electrode 199 is rectangular, and includes a cruciform stem made up of a transverse stem 193 and a longitudinal stem 192 perpendicular thereto. The basic electrode 199 is divided into a first sub-area Da, a second sub-area Db, a third sub-area Dc, and a fourth sub-area Dc by the transverse strike line 193 and the vertical strike line 192, And the sub regions Da, Db, Dc, and Dd include a plurality of first to fourth fine branches 194a, 194b, 194c, and 194d.

The first fine arcuate portion 194a extends obliquely from the transverse arcuate portion 193 or the vertical arbor portion 192 in the upper left direction and the second fine arbor portion 194b extends obliquely from the transverse arcuate portion 193 or the vertical stripe portion 192, And extends obliquely from the base 192 in the upper right direction. The third fine arcuate portion 194c extends from the transverse arcuate portion 193 or the vertical arbor portion 192 in the lower left direction and the fourth fine arbor portion 194d extends from the transverse arbor portion 193 or the vertical arbor portion 192. [ And extends obliquely downward in the right-down direction from the upper side 192.

The first to fourth fine branches 194a, 194b, 194c, and 194d form an angle of about 45 degrees or 135 degrees with respect to the gate line 121 or the transverse strike portion 193. Further, the fine branches 194a, 194b, 194c, and 194d of the neighboring two sub-regions Da, Db, Dc, and Dd may be orthogonal to each other.

Although not shown, the width of the fine branch portions 194a, 194b, 194c, and 194d may be increased toward the transverse branch portion 193 or the vertical branch portion 192. [

Referring again to FIGS. 2 to 5, the first and second sub-pixel electrodes 191a and 191b each include one basic electrode 199. The area occupied by the second sub-pixel electrode 191b in the entire pixel electrode 191 may be larger than the area occupied by the first sub-pixel electrode 191a. At this time, the second sub- The size of the basic electrode 199 is formed to be different from the area of the pixel electrode 191a by 1.0 to 2.2 times.

The second sub-pixel electrode 191b includes a pair of branches 195 extending along the data line 171. The second sub- The branches 195 are located between the first sub-pixel electrode 191a and the data lines 171a and 171b and are connected to the lower ends of the first sub-pixel electrodes 191a. The first and second sub-pixel electrodes 191a and 191b are physically and electrically connected to the first and second drain electrodes 175a and 175b through contact holes 185a and 185b, And receives the data voltage from the electrodes 175a and 175b.

Next, the upper display panel 200 will be described.

In the upper panel 200, a common electrode 270 is formed on a transparent insulating substrate 210.

A gap material 363 for maintaining a gap between the upper display panel 200 and the lower display panel 100 is formed on the gate line 121 or the thin film transistor. The spacers 363 formed on the thin film transistors overlap the first and second source electrodes 173a and 173b and the first and second drain electrodes 175a and 175b and are connected to the openings of the first barrier ribs 361a G and the contact hole 185b of the upper protective film 180q on the pixel electrode 191. [

On the inner surfaces of the lower panel 100 and the upper panel 200, alignment films 11 and 21 are applied, respectively, and they may be vertical alignment films.

Polarizers (not shown) may be provided on the outer surfaces of the lower panel 100 and the upper panel 200.

A liquid crystal layer 3 is interposed between the lower panel 100 and the upper panel 200. The liquid crystal layer 3 includes an alignment polymer formed by irradiating a plurality of liquid crystals 310 and the alignment assisting agent 50 with light.

The liquid crystal 310 has a negative dielectric anisotropy and is oriented such that its long axis is substantially perpendicular to the surface of the two display panels 100 and 200 in the absence of an electric field.

When a voltage is applied to the pixel electrode 191 and the common electrode 270, the liquid crystal 310 responds to an electric field formed between the pixel electrode 191 and the common electrode 270, so that the long axis thereof is perpendicular to the direction of the electric field . The degree of change of the polarization of the incident light to the liquid crystal layer 3 varies depending on the degree of tilting of the liquid crystal 310. The change of the polarized light is represented by a change of the transmittance by the polarizer and the liquid crystal display displays the image.

The direction in which the liquid crystal 310 is inclined is determined by the micro branches 194a, 194b, 194c and 194d of the pixel electrode 191 and the liquid crystal 310 is aligned in the longitudinal direction of the micro branches 194a, 194b, 194c and 194d As shown in Fig. Since one pixel electrode 191 includes four sub-regions Da, Db, Dc, and Dd having different lengths of the micro branches 194a, 194b, 194c, and 194d, the direction in which the liquid crystal 310 is inclined And four domains having different directions of alignment of the liquid crystal 310 are formed in the liquid crystal layer 3. By thus changing the direction in which the liquid crystal is inclined, it is possible to improve the viewing angle of the liquid crystal display device.

The orientation polymer formed by the polymerization of the alignment aid 50 serves to control the pre-tilt, which is the initial alignment direction of the liquid crystal 310. The alignment aid 50 may be a conventional reactive mesogen.

The alignment aid 50 has a shape similar to that of a liquid crystal and has a core group and a terminal group connected to the core group.

The alignment aid 50 according to the embodiment of the present invention has a mesogen as a center portion and a photo-polymerizable group as a terminal group.

The mesogen includes a structure in which two or more aromatic or aliphatic cyclic compounds are connected to the center thereof, and includes, for example, a naphthalene group represented by the formula (A), a biphenyl group represented by the formula (B) A bisphenol A group represented by the formula (D), and a halogen atom-containing derivative of the compound represented by the formula (D).

(A)

[Chemical Formula B]

≪ RTI ID = 0.0 &

[Chemical Formula D]

Here, the halogen atom is substituted at the hydrogen atom position of the cyclic compound, and the halogen atom is positioned to be structurally symmetric, and may be electrically neutral. The halogen atom includes one selected from fluorine, chlorine, bromine and iodine.

The photopolymerization unit is not limited as long as it is a functional group capable of being polymerized by receiving light, and may include, for example, one selected from an acrylic group represented by the formula (F) and a methacryl group represented by the formula (G)

[Chemical Formula F]

[Formula G]

The alignment aid 50 may further include a chain alkyl group having 3 to 12 carbon atoms positioned between the mesogen and the photopolymerization unit. Such a chain type alkyl group is positioned between the mesogen and the photopolymerization unit to control the chain length, thereby enhancing the polymerization property when the alignment aid 50 receives light.

The orientation aid (50) may be selected from the compounds represented by the following general formulas (1) to (8).

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

In the above Chemical Formulas 1 to 8, two aromatic rings are connected by a single bond line, and halogen atoms bonded to the aromatic ring may be positioned to be structurally symmetric. In particular, the halogen atoms may be positioned to be symmetrical about an axis perpendicular to the single bond line connecting the aromatic rings to each other. And, the alignment aid may be electrically neutral.

In the general formulas (1) and (5), the halogen atom is located near the axis perpendicular to the single bond line, so that the halogen atom is almost electrically neutral. (A ') and the fourth portion (b') in the case where a halogen atom is bonded in the first portion (a) and the second portion (b) in which the carbon of the aromatic ring is located as shown in the following chemical formula E, Is nearly electrically neutral when halogen atoms are bonded. This corresponds to the above formulas (1) and (5), and this case is defined as quasi-neutrality below.

(E)

The alignment aid 50 described above may be contained in an amount of about 0.1 wt% to 10 wt% with respect to the content of the liquid crystal 310. If the content of the liquid crystal 310 is less than about 0.1 wt%, the function of controlling the linear gradient of the liquid crystal 310 is not performed. If the content of the liquid crystal 310 is more than about 10 wt%, the content of the liquid crystal 310 may be decreased. In particular, the alignment aid 50 may be contained in an amount of about 0.1 wt% to 0.5 wt% with respect to the content of the liquid crystal 310.

The alignment aid 50 may be polymerized by light.

6 will be described with reference to FIGS. 2 to 5. FIG.

6 is a schematic view showing a method of forming a line inclination of a liquid crystal by an alignment assisting agent according to an embodiment of the present invention.

First, the thin film transistor display panel 100 and the common electrode panel 200 are manufactured.

The lower panel 100 is manufactured in the following manner.

A plurality of thin films are stacked and patterned on the substrate 110 to form the gate lines 121 including the gate electrodes 124a and 124b, the gate insulating film 140, the semiconductors 154a and 154b, and the source electrodes 173a and 173b The data lines 171a and 171b, the drain electrodes 175a and 175b, and the lower protective film 180p are sequentially formed.

Subsequently, a barrier rib 361 is formed on the lower protective film 180p, a color filter 230 is filled in a region surrounded by the barrier ribs 361, and an upper protective film 180q is formed on the color filter 230.

A conductive layer such as ITO or IZO is laminated on the upper protective film 180q and patterned to form a vertical portion 192, a lateral portion 193 and a plurality of fine branches 194a , 194b, 194c, and 194d.

Then, the alignment film 11 is coated on the pixel electrode 191.

The upper display panel 200 is manufactured in the following manner.

A common electrode 270 is formed on the substrate 210. Then, the alignment film 21 is applied on the common electrode 270.

Next, the lower panel 100 and the upper panel 200 manufactured as described above are assembled, and a mixture of the liquid crystal 310 and the above-described alignment aid 50 is injected therebetween, (3). However, the liquid crystal layer 3 may be formed by dropping a mixture of the liquid crystal 310 and the alignment aid 50 on the lower panel 100 or the upper panel 200.

Next, referring to FIG. 6A and FIG. 5, a voltage is applied to the pixel electrode 191 and the common electrode 270. The liquid crystal 310 and the alignment assisting agent 50 are inclined in the direction parallel to the longitudinal direction of the fine branches 194a to 194d of the pixel electrode 191 by the voltage application. The liquid crystal 310 located in the vicinity of the alignment film 11 maintains the vertical alignment by the alignment film chain 11a.

In this way, the light 1 is irradiated while a voltage is applied between the pixel electrode 191 and the common electrode 270. The light (1) uses a material having a wavelength capable of polymerizing the alignment aid (50), and ultraviolet light or the like may be used. Thus, the alignment assisting agents 50 gathered at the adjacent positions are optically polymerized to form the polymer 50a. Such a polymer 50a can control the linear inclination of the liquid crystal 310. [

The voltage to be applied to the pixel electrode 191 and the common electrode is a direct current voltage, the size thereof may be 5 V to 20 V, and the energy of the irradiating light 1 may be 5 J / _cm ² to 10 J / _cm ² . If the energy to be irradiated is less than 5 J / _cm ² , the response speed may decrease. If the energy to be irradiated is larger than 10 J / _cm ² , the response speed may increase but the contrast ratio may decrease.

Subsequently, as shown in FIG. 6B, the voltage between the pixel electrode 191 and the common electrode 270 is turned off.

And then the liquid crystal layer 3 is irradiated with light in a state where the voltage is turned off to the pixel electrode and the common electrode to increase the polymerization rate.

The liquid crystal layer 3 includes the polymer 50a polymerized by light and the unpolymerized alignment assistant 50 but the alignment assistant 50 according to the embodiment of the present invention is capable of improving the polymerization reactivity as described above And thus reduce the amount of the alignment aid not being photopolymerized. The remaining amount of the unpolymerized alignment aid in the liquid crystal display according to the embodiment of the present invention is about 5% by weight or less based on the total content of the alignment aid.

When the content of the unpolymerized alignment aid is high, the evaluation of the afterimage causes a difference in line slope in the black / white display portion, and this difference can be visually recognized as an afterimage from the outside.

The response characteristics and the reaction efficiency of the liquid crystal display according to the present invention will be described with reference to comparative examples.

Since the biphenyl group corresponding to the mesogen is electrically neutral, there is no restriction on the movement of the mesogen by the electric field, so that the curing reaction with neighboring mesogens occurs well. Therefore, the residual mesogens are small and the afterimage is reduced.

 (1A)

The following chemical formula [1B] of Comparative Example 2 has an electrically negative chemical structure, and when the vertical electric field of the upper and lower plates is applied at the time of voltage application, the motion of the mesogen is fixed and the probability of reaction collision with the neighboring mesogen becomes lower, .

[1B]

7 and 8 are graphs showing the relationship between the amount of residual mesogens and the amount of residual mesogens when the mesogens of the alignment assisting agent are represented by the following chemical formula [1C] in the liquid crystal display devices according to the embodiments of the present invention and the chemical formulas [1A] and [ This is a graph comparing the response speed.

[1C]

As shown in the graphs of FIGS. 7 and 8, in the liquid crystal display device according to the embodiment of the present invention, the alignment assisting agent contains a halogen atom in the aromatic ring between the photopolymerization units and is positioned such that the halogen atom is structurally symmetrical, Because it is neutral, the amount of residual mesogen is reduced to the extent similar to Comparative Example 1, and the response speed is improved.

As described above, the liquid crystal display device according to the embodiment of the present invention can uniformly control the line inclination of the liquid crystal by including the alignment assistant, and by including the alignment assistant having the specific structure at this time, The remaining amount of the adjuvant can be reduced. This can reduce the afterimage that may occur due to the unpolymerized alignment aid and improve the display characteristics.

A liquid crystal composition according to another embodiment of the present invention includes a liquid crystal and an orientation polymer. The orientation polymer serves to control the pre-tilt, which is the initial alignment direction of the liquid crystal. The alignment aid has a shape similar to that of the liquid crystal and has a core group and a terminal group connected to the core group.

The alignment aid according to an embodiment of the present invention may have a mesogen as a central portion and a photo-polymerizable group as a terminal group. The alignment polymer is formed by irradiating the liquid crystal and the alignment assistant with light, and the alignment assistant comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen. The orientation aid is electrically neutral or quasi-neutral. The description of the alignment aid contained in the liquid crystal layer described above with reference to Figs. 1 to 8 also applies to the liquid crystal composition according to the embodiment of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

1 is an equivalent circuit diagram of a pixel of a liquid crystal display according to an embodiment of the present invention.

2 is a layout diagram of a liquid crystal display device according to an embodiment of the present invention.

3 is a cross-sectional view taken along line III-III 'of FIG.

4 is a plan view showing a pixel electrode.

5 is a plan view showing a basic electrode in a liquid crystal display device according to an embodiment of the present invention.

6 is a schematic view showing a method of forming a line inclination of a liquid crystal by an alignment assisting agent according to an embodiment of the present invention.

FIGS. 7 and 8 are graphs showing a comparison between the amount of residual mesogens and the response speed between the liquid crystal display device and the comparative example according to an embodiment of the present invention

Description of the Related Art

3 liquid crystal layer 50 orientation aid

100 Lower panel 200 Upper panel

300 liquid crystal display panel assembly 310 sealing material

121 gate lines 131, 135 sustain electrode lines

140 Gate insulating films 154a and 154b Semiconductor

163b, 165b The resistive contact members 171a,

173a, 173b Source electrodes 175a, 175b Drain electrodes

180p lower protective film 180q upper protective film

361 Bulkhead 230 Color Filter

270 common electrode 310 liquid crystal

363 Interval material 220 Light shielding member

321 Light-shielding auxiliary member 235 Projecting member

320a auxiliary gap material

Claims (26)

The first substrate, A second substrate facing the first substrate, An electric field generating electrode formed on at least one of the first substrate and the second substrate, And a liquid crystal layer interposed between the first substrate and the second substrate and having a liquid crystal and an orientation polymer, The orientation polymer is formed by light irradiation of an orientation assisting agent, Wherein the alignment aid comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, Wherein the alignment assisting agent is electrically neutral or semi-neutral. The method of claim 1, Wherein the halogen atom is connected to the aromatic ring between the light-curing units and is structurally symmetrical. 3. The method of claim 2, Wherein the mesogen is one of naphthalene, biphenyl, and bisphenol A to which the halogen atom is bonded. 4. The method of claim 3, Wherein the halogen atom comprises one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine. 5. The method of claim 4, Wherein the light curing unit comprises at least one selected from an acrylic group and a methacryl group. The method of claim 5, The alignment aid may be represented by any one of the following formulas (1) to (8) [Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

Lt; RTI ID = 0.0 > 1, < / RTI > The method of claim 1, Wherein the orientation-assisting agent is contained in an amount of 0.1 wt% to 0.5 wt% with respect to the content of the liquid crystal. The method of claim 1, Wherein the electric field generating electrode has a plurality of fine slits. The method of claim 1, Wherein the first substrate is a thin film transistor substrate, the second substrate is a common electrode substrate, Wherein at least one of a color filter and a black matrix is formed on the thin film transistor substrate. Forming a first display panel on which pixel electrodes are formed, Forming a second display panel on which a common electrode is formed, Attaching the first display panel and the second display panel together, Forming a liquid crystal layer including a liquid crystal and an alignment assisting agent between the first display panel and the second display panel, Applying a voltage between the pixel electrode and the common electrode, Irradiating the liquid crystal layer with light while applying a voltage between the pixel electrode and the common electrode to photo-polymerize the alignment assistant Lt; / RTI > Wherein the alignment aid comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, Wherein the alignment assistant is electrically neutral or quasi-solid. 11. The method of claim 10, Wherein the halogen atom is connected to an aromatic ring between the light-curing units and is positioned to be structurally symmetric. 12. The method of claim 11, Wherein the mesogen is one of naphthalene, biphenyl, and bisphenol A to which the halogen atom is bonded. The method of claim 12, Wherein the halogen atom comprises one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine. The method of claim 13, Wherein the light curing unit comprises at least one selected from an acrylic group and a methacryl group. The method of claim 14, The alignment aid may be represented by any one of the following formulas (1) to (8) [Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

And a compound represented by the following general formula (1): " (1) " 11. The method of claim 10, Wherein the voltage applied to the pixel electrode and the common electrode is a direct current voltage, and the direct current voltage is 5V to 20V. 11. The method of claim 10, And irradiating the liquid crystal layer with light in a state in which the voltage is turned off to the pixel electrode and the common electrode. The method of claim 17, The method of the pixel electrodes and energy is 20J / _cm ² to 60J / _cm ² of the liquid crystal display device is irradiated with light in a state of turning off the voltage to the common electrode. 11. The method of claim 10, Wherein the energy for irradiating light with a voltage applied to the pixel electrode and the common electrode is 5 J / _cm ² to 10 J / _cm ² . 11. The method of claim 10, Wherein at least one of a color filter and a black matrix is formed on the first display panel, and the liquid crystal layer is irradiated with light through the second display panel. Liquid crystal and an orientation polymer, The alignment polymer is formed by irradiating the liquid crystal and the alignment assisting agent with light, Wherein the alignment aid comprises a mesogen having a halogen atom and a photopolymerizable group bonded to the mesogen, wherein the alignment aid is electrically neutral or subordinate. 22. The method of claim 21, Wherein the halogen atom is connected to the aromatic ring between the photopolymerization units and is positioned to be structurally symmetrical. The method of claim 22, Wherein the mesogen is one of naphthalene, biphenyl, and bisphenol A to which the halogen atom is bonded. 24. The method of claim 23, Wherein the halogen atom comprises one selected from the group consisting of Fluorine, Chlorine, Bromine, and Iodine. 25. The method of claim 24, The alignment aid may be represented by any one of the following formulas (1) to (8) [Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

Lt; RTI ID = 0.0 > 1, < / RTI > 22. The method of claim 21, Wherein the orientation aid is contained in an amount of 0.1 wt% to 0.5 wt% with respect to the content of the liquid crystal.

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